Keyboard tone bar percussion instrument



Dec. 20, 1960 5 Sheets-Sheet 1 Dec. 20, 1960 SCHMITT 2,965,451

KEYBOARD TONE BAR PERCUSSION INSTRUMENT Filed Feb. 12, 1954 N 5 Sheets-Sheet 2 FIG 5 INVE/WUP Dec.20,1960 R MITT 2,965,451

KEYBOARD TONE BAR PERCUSSION INSTRUMENT Filed Feb. 12, 1954 5 Sheets-Sheet 3 INVENTOP Dec. 20, 1960 sc 2,965,451

KEYBOARD TONE BAR PERCUSSION INSTRUMENT Filed Feb. 12, 1954 '5 Sheets-Sheet 4 INVENTOP WW4 lm 1960 R. SCHMITT 2,965,451

KEYBOARD TONE BAR PERCUSSION INSTRUMENT Filed Feb. 12, 1954 5 Sheets-Sheet 5 United States Patent M KEYBOARD TONE BAR PERCUSSION INSTRUMENT Richard Schmitt, Fleyerstr. 105, Hagen, Westphalia, Germany; Lieselotte Schmitt, sole heir of said Richard Schmitt, deceased Filed Feb. 12, 1954, Ser. No. 409,968

Claims priority, application Germany Feb. 14, 1953 2 Claims. (Cl. 84-403) The invention relates to a keyboard percussion instrument in which the tones are produced, not by strings, but by tuned metal cantilever bars of various lengths struck by hammers.

There are known means of attaching tone-producing elements to a common metal frame fixedly bolted to the ends of the front wall of a piano cabinet. As a result of this fixed support at both ends, the vibrations of the bars become entirely dilferent according to the distances of the several metal bars (tone-producing elements) from the points of support of the metal frame. Satisfactory resonance is not obtained. The tones produced on the known instrument are brief, explosive and staccato, and a harmonious blending of the individual tones produced by successive strokes upon the metal bars is not obtainable on such an instrument.

There are likewise known methods of mounting the metal frame in which the bars are fixed, not fixedly supported, but in a sort of floating suspension, so that all parts of the system participate uniformly in the vibration. Mounting of the frame on a longitudinal rail, of prismatic and preferably wedge-shaped cross-section, passing underneath the frame and supported'on a ledge with interposition of metal springs, the frame being attached to the ledge with a plurality of clamps or like means, is also known. 1

Finally, there is no novelty in making the metal bars (tone-producing means) fixed in the frame of differvent lengths and tuning them like the strings of a piano,

whose purpose they serve.

However, it has been found that the known frame and bars will not produce thefull harmonious tonal effect of a string. piano, and that in order to eliminate this disadvantage, i.e. in order to achieve the harmony and full sonority desirable in such instruments, a more fundamental, more far-reaching and more radical design of the frarne as well asof the tone-producing means and their attachment is required.

According to the invention, the frame tapers longitudinally in such manner that the frame is thickest where the slenderest and longest bars are inserted, and becomes smaller with decreasing length and increasing thickness of the bars. The choice of an ideal metal for the frame is likewise essential, and it has been found that cast steel should preferably be used. It is also essential for the desirable sonority that the bars themselves not be equal in diameter as heretofore, but, according to the present invention, of decreasing thickness, the bars in the bass being substantially thinner as well as longer than those in the treble. The bass bars are about 40-50 cm. in length, the treble about 7-8 cm. The long bars, wh eTl struck by the hammers, have far more latitude of vibration than the short bars. If the long bars were to be inserted in the treble, their tone would be hollow. Conversely, the short bars would not sound at all in the bass section, i.e. in the thickest part of the frame,

whence the novel principle that the longer the bar, the

thicker the metal frame should be at that point, and

ICE

vice versa. The vibration of the bars is in accord with the vibration of the frame, or in other words the thickness of the frame varies directly as the length of the bars if the desired sonority is to be obtained. This implies a further feature of the invention, still based on the frame, namely that the bars must be of different thicknesses. They are about 3-5 mm. in the bass and about 7-8 mm. in the treble. For it has been found that if the bars in the bass are as thick as those in the treble, the overtones will drown out the fundamental.

Finally, the insertion of the bars is likewise essential, both for the purpose of fixing them in the frame and for their proper vibration and the subordination of overtones.

Other important novel and advantageous features of the invention will be noted in the course of the following description.

The object of the invention is represented, by way of example and not of restriction, in the accompanying drawing, wherein:

Fig. 1 shows a cross-section of the essential portion of one embodiment of the instrument according to the invention;

Fig. 2 is a corresponding top view;

Fig. 3 shows a section along the line A--B in Fig. 1;

Figs. 4 and 5 show the insertion of the tone-producing elements to an enlarged scale;

Fig. 6 shows another embodiment of a keyboard percussion instrument according to the invention, seen from above;

Fig. 7 shows the same embodiment with sounding board removed;

Fig. 8 shows a section along the line CD in Fig. 6;

Fig. 9 shows the frame attachment in partial section along the line EF in Fig. 7;

Fig. 10 shows a bass bar;

Fig. 11 shows a bar insertion in partial section;

Fig. 12 shows a vibration damper in section;

. Figs. 13 and 14 show alternative embodiments of frame attachments as in Fig. 9;

Fig. 15 shows the frame attachment according to Fig. 14 in side view;

Figs. 16 and 17 show alternative embodiments of the insertion of tone-producing elements.

In the drawing, the otherwise known percussion action, which is actuated by striking the keys, has been omitted. It occupies the conventional position underneath the toneproducing elements, or in front of them as in Fig.2. In the frame 1, the bars are shown arranged in their conventional order. The frame 1 tapers down uniform ly in cross-section from the insertion of the longest bars 2 to the insertion of the shortest bars 3. The bars, reading from 2 to 3, increase in diameter and decrease in length. The bars 2 are in the bass and the bars 3 in the treble. In addition, the thin bars 2 are provided with slidable and fixable sleeves 4 to damp their vibration, as well as to permit exact tuning of their pitch. The bars, as may be seen in particular in Figs. 4 and 5, have a taper 5 at the point of insertion, followed by a cylindrical shoulder 6 of greater thickness. The shoulder 6 fits into a hollow screw 7, which is slit so as to grasp the shoulder 6 tightly when screwed into a tapered threaded hole 8. In the embodiment according to Fig. 4, a special tightening-part 9 is provided, which is tapered and fits into a corresponding hole in the frame 1. By means of a separate nut 11 bearing on the frame 1 and engaging a stud on the wedge 9, the bar is held clamped in place. The frame 1, in otherwise known manner, rests by two or more prismatic rails 12 on metal pins 13, which in turn are supported on leaf springs 14 lying bridge-fashion on wooden pins 15 separated by felt pads 16 from the sounding board 17. Above, the

frame 1 is held by set screws 18 mounted in the wooden frame of the instrument. However, to avoid undesirable conduction of sound and overtones, these do not bear directly on the frame, 1 but on hardwood blocks 19. The lower sounding board 21 may alternatively be of the same extent as the upper sounding board 22 and be provided with openings 23. The tone is substantially amplified by the sounding boards. A top plate 24, covering the system, serves to damp overtones and reinforce the fundamental. As shown in Figs. 1 and 2, the top plate 24 and sounding board 22 are absent; together they form a box supported partly by the end pieces 25 and partly by the walls 26. Between the treble bars 3, damping means, for example strips of leather or rubber 27, are passed over and under.

In accordance with the construction shown in Figs. 6-9, in the casing 28, in which a keyboard 29 having hammers not shown in the drawings is arranged, there is mounted on a block supporting board 31 a block 32 which is widened towards the bass end. The sounding rods 2, 3, secured in the block 32 are covered by a sounding board 33 secured above block 32. On the block 32 at the fastening points thereof, there is a nonsounding metal plate 34, for example of aluminum and at the base end, the block 32 is held down by an upper wooden block 35, which is secured to lower block 37 by means of screws 36. Placed on the stay 35 and below the abutment 37, which latter two members may be fashioned in wood, are plate springs 38, which are tensioned by the screws 36. The sounding rods 2, 3, (Fig. are clamped (Fig. 11) in the block 32 by means of substantially pear-shaped clamping sleeves 39, which are drawn into conical openings 41 of the block 32 by adjusting screws 40 and which enclose the clamped ends of the sounding rods 2, 3. The bass rods 2 are provided with grooves 42 and carry, on their freely vibrating ends, caps 43 of non-sounding material. Vibration dampers 44 (Fig. 7) are disposed on the treble rods 3 and consist (Fig. 12) of a slotted ledge or bracket 45, on which there is fastened a plate spring 46 carrying a rubber flap 48 on a holder 47, the flap pressing against the freely vibrating end of the rod 3. The sounding board 33 is of double construction and encloses a hollow space 49. It is supported with one ledge 51 on the block 32 and is clamped in a freely vibrating manner. The board 33 is clamped underneath brackets 52 of the rear wall of the casing 28 and connected with the block supporting board 31 by means of screws 53. Clamped between the sounding board 33 and block supporting board 31, conveniently only at the bass end, there is a cross piece 54 used for better transmission of the vibrations. Consequently, this cross piece 54 transmits the vibrations of the sounding board 33 to the block supporting board 31, by which a rich tone is produced and the overtones of the bass rods are damped.

Fig. 13 shows a frame attachment as in Fig. 9, except that the attachment bolts 36 pass through the frame 32. In Fig. 15, as hearing, a round pin 13 is placed under the frame 32 in lengthwise direction of the latter. The pin 13 rests on a leaf spring 14 bearing on hardwood laths 15. The laths 15 rest on the panel 31, hearing on or glued to a cushion 37. On the frame, there is a strap 56 of atonal metal, held down by a leaf spring 38. Attachment screws 36 pass through the leaf spring 38, the panel 31, the cushion 37 and a metal plate 57 placed under the cushion, and hold down the frame 32 on the panel.

The end of the tone bar shown in Fig. 16, beyond a taper 5, has a taper insertion shoulder 58 fitting into a taper insertion hole 41 in the frame 32. Beyond the insertion shoulder 58, the tone bar continues in a stud 59 covered with a blind nut 11 drawing the bar into the insertion hole. In Fig. 17, the conical taper at the insertion end of the tone bar, 61, has a cylindrical continua tion 62, following which the end of the bar is enlarged to the original cross-section but provided with a recess 63 such as to form shoulders 64 grasped by the wedge screw 39.

I claim:

1. A keyboard percussion instrument comprising a frame and a supporting panel, metal bars of varying cross-sectons, inserted in said frame and adapted to produce varying musical pitches, said metal bars including bass bars and treble bars, said frame tapering down in cross section from the point of insertion of bass bars to the point of insertion of the treble bars, supporting nonresonant elements mounting said frame on said supporting panel, an upper wooden block and a lower wooden block attached to said frame, said frame having bores for receiving said metal bars and mounting means for said frame, and control means on the bars for modifying the vibrations of said metal bars.

2. Keyboard percussion instrument according to claim 1 wherein pear shaped clamping sleeves are provided at one end for attaching the bars, said upper wooden block having conical openings adjustably receiving said sleeves.

References Cited in the file of this patent UNITED STATES PATENTS 436,385 Steck Sept. 16, 1890 1,269,511 Roberge June 11, 1918 2,159,491 Rose May 23, 1939 2,263,106 Sebouh Nov. 18, 1941 2,463,543 Kunz Mar. 8, 1949 2,722,154 Neumark Nov. 1, 1955 FOREIGN PATENTS 478,999 Great Britain Jan. 28, 1938 663,662 Great Britain Dec. 27, 1951 

1. A KEYBOARD PERCUSSION INSTRUMENT COMPRISING A FRAME AND A SUPPORTING PANEL, METAL BARS OF VARYING CROSS-SECTIONS, INSERTED IN SAID FRAME AND ADAPTED TO PRODUCE VARYING MUSICAL PITCHES, SAID METAL BARS INCLUDING BASS BARS AND TREBLE BARS, SAID FRAME TAPERING DOWN IN CROSS SECTION FROM THE POINT OF INSERTION OF BASS BARS TO THE POINT OF INSERTION OF THE TREBLE BARS, SUPPORTING NONRESONANT ELEMENTS MOUNTING SAID FRAME ON SAID SUPPORTING PANEL, AN UPPER WOODEN BLOCK AND A LOWER WOODEN BLOCK ATTACHED TO SAID FRAME, SAID FRAME HAVING BORES FOR RECEIVING SAID METAL BARS AND MOUNTING MEANS FOR SAID FRAME, AND CONTROL MEANS ON THE BARS FOR MODIFYING THE VIBRATIONS OF SAID METAL BARS. 